<!DOCTYPE html>
<html class="reftest-wait">
  <!-- Test: if button is not disabled, it is candidate for constraint validation
             and should be affected by :valid pseudo-class. -->
  <link rel='stylesheet' type='text/css' href='style.css'>
  <body onload="document.getElementById('b').removeAttribute('disabled'); document.documentElement.className='';">
    <button class='valid' id='b' disabled></button>
  </body>
</html>
